Hey Everyone, was out at MSP today when I noticed a NWA dc-9 on rwy 30R. The rwy was closed, and Emergency vehicles were out on the rwy for some time. In the end the aircraft was towed off the rwy with a tug, does anyone have any info on what happened?? Sorry but I did not catch the reg of the bird!
CC

>>>In the end the aircraft was towed off the rwy with a tug, does anyone have any info on what happened??

9 times out of 10, if an aircraft has to be towed off a runway, it means that they suffered some kind of hydraulic system problem...

It's been years since I dispatched DC-9s, so my brain has dumped most of my systems knowledge. The 737-200 is an aircraft from the same timeframe, and its nosewheel steering ran only off the "A" hyraulic system. Thus, if the "B" system failed you could taxi in normally, but if it was the "A" system that failed, you had to be towed in.

I presume here that the older DC-9s only run their nosewheel steering off one of the multiple hydraulic systems, whatever Douglas called them...

It's been a while sine working the DC-9/MD-80 but I believe that you can still taxi with the loss of one hydraulic system. Each steering actuator runs off of separate hydraulic systems unlike the older Boeings which run off of one system.

That is possible but unlikely. They could have lost only one system and the crew thought it would be safer to get towed back to the gate, although systems-wise one hydraulic system is sufficient for taxi. (I just reviewed my training manuals)

A bit off topic but it is interesting to note that airplane's that can operate flight controls without hydraulic pressure tend to prioritize hydraulic pressure to STOPPING the aircraft after it touches down. The DC8 (the only craft I know inside and out) has hydraulic accumulors mainly for braking, thrust reverse and spoilers. If one were to look at the DC8 manual, stopping the aircraft after touchdown is the only thing the designers were concerned about. All flight controls on that size aircraft are manageable without hydraulic pressure except maybe rudder.